BALI, Indonesia (Reuters) - A small band of protesters holding aloft a banner disrupted a large HIV/AIDS conference in Indonesia on Wednesday to demand access to drugs to treat HIV patients dying from hepatitis C.

The World Health Organisation says 4-5 million people living with HIV/AIDS around the world are also infected with hepatitis C, a disease that can cause liver failure.

Protesters said pegylated interferon, a drug marketed by Roche and intended to flush out the virus, costs $1,500 a month.

"Shame on you Roche, shame on you!" they chanted.

Roche was not immediately available for comment.

Most people infected with both HIV and hepatitis C are injecting drug users. Both diseases are blood borne and transmission is through the sharing of used needles and other equipment, even cotton swabs.

Although international health agencies and governments have sought to make HIV drugs available to sufferers, high costs limit access to treatment for hepatitis C in most countries.

According to the WHO, injecting drug users are excluded from treatment in many countries due to fears of the interaction between drugs and the likelihood of reinfection.

But Nanao Haobam, who is infected with both viruses, said such an approach was untenable as patients were dying.

"In my community back home, I have seen more than 50 (HIV positive) people die because of HCV. There must be many more than that," he said.

Haobam, 38, is a former injecting drug user and now an HIV/AIDS activist in Bangkok. He told Reuters he learned he was HIV positive in 2000 and was diagnosed with HCV two years later.

"I was on treatment, but that didn't get rid of all the HCV. I recently saw a doctor and he advised me to start treatment for hepatitis as I am now in the initial stage of cirrhosis," he said.

"But I just can't afford it, I have to leave this matter in the mercy of God."

Failure to treat cirrhosis, the hardening of the liver, will lead to a patient requiring a transplant or dying.

The prevalence of chronic HCV infection among patients with HIV in western Europe and the United States is estimated at 25 to 30 percent. In Asia, 80 to 90 percent of injecting drug users who are HIV positive are co-infected with HCV.

Co-infection rates average over 40 percent in eastern Europe and extend to 70 to 95 percent in Estonia, Russia and Ukraine.

"If governments can't make the drug available, the least they can do is to get rid of the patent, so that generic versions can be made," Haobam said.